1. Field
The invention is in the field of measuring devices used to determine whether building code requirements have been met for steel reinforcing bars used in structural concrete.
2. State of the Art
The steel bars used in reinforced concrete construction, normally referred to as "reinforcement", "reinforcing bars", or simply "bars", are bent into shapes referred to as typical bar bends. One group of typical bar bends are known as "standard hooks". Included in the standard hooks are 90.degree. and 180.degree. end hooks, 90.degree. and 135.degree. stirrup and tie hooks, and 135.degree. seismic stirrup and tie hooks.
The bends are at a required angle, plus or minus 21/2.degree., about an established diameter. Bends at the end of the bar have end extensions extending therefrom. Construction industry institutes and related societies such as the Concrete Reinforcing Steel Institute [CRSI], the American Concrete Institute [ACI], and the American Society of Testing Materials [ASTM] have promulgated minimum standards relating to reinforcing bars, the diameter of the bar bends, and the lengths of end extensions. The standards promulgated by such institutes have been adopted by the International Conference of Building Officials and are incorporated in the building codes of many local governmental bodies.
Any bar bend that is measured to have a bend diameter or end extension less than the established minimum is in violation of the code. Any bend angle that is outside the plus or minus 21/2.degree. allowance from the established 90.degree., 135.degree., or 180.degree. bends is in violation of the code. Such bars may be subject to premature fracture when put under load. Decisions on what to do when bends do not meet the code are the responsibility of the design professionals and any local building department. However, site inspectors are charged with the responsibility of inspecting steel reinforcement bars to see that, among other criteria, their bend angles, diameters, and end extensions are within the established standards. Site inspectors must somehow make this determination. However, so far as is known, the prior art has not provided any means or methods for determining whether bar bends and the end extensions of these bends are less than the established minimums.